Table 3.

Key studies investigating ADHD and choline.

Author, Year	Study Design/Approach	Age	No. of Participants	Key Findings
Alger et al. (2021) [78]	Case-control	8–13 y	n = 23 ADHD + PAE n = 19 ADHD − PAE n = 28 TD	Cho findings were less prominent in this study.
Borlase et al. (2020) [82]	Randomized PC trial	11 y (mean)	n = 27 ADHD (non-medicated)	In the treatment group (12 capsules/day; dose NS) there was a trend for decreased choline in the striatum.
Wozniak et al. (2020) [81]	Randomized, DB, PC trial (9-months)	2–5 y	n = 15 FASD Cho n = 16 FASD placebo	Children receiving Cho (1.25 g. Cho bitartrate powder delivering 513 mg/day Cho) had higher non-verbal intelligence, higher visual-spatial skill, higher working memory ability, better verbal memory and fewer behavioral symptoms of ADHD than those receiving the placebo.
O’Neill et al. (2019) [79]	Case-control	7–17 y	n = 44, by subgroup	Low Cho may stem from abnormal Cho metabolism.
Wiguna et al. (2012) [86]	Prospective analysis	9 y (mean)	n = 21 ADHD	The Cho/creatine ratio decreased 12% in the right prefrontal cortex after stimulant treatment.
Kronenberg et al. (2008) [84]	Spectroscopic test-retest study	Adults	n = 7 ADHD	Analysis of regional brain showed a significantly decreased signal of Cho-containing compounds following treatment with MPH.
Carrey et al. (2003) [83]	Magnetic resonance spectroscopy	NR	n = 14 ADHD	Cho metabolites did not demonstrate any change in response to medication.
Jin et al. (2001) [80]	Magnetic resonance spectroscopy	NR	n = 12 B ADHD n = 10 controls	In ADHD children the bilateral striatum Cho/Cr ratio showed a mild unilateral increase. There appears to be mild hyperactivity of the cholinergic system.

Key: B, boys; Cho, choline; DB, double-blind; FASD, fetal alcohol spectrum disorder; MPH, methylphenidate; NR, not reported; NS, Not clearly specified; PC, placebo-controlled; TD, typical development; y, years.